The study is aimed to treat low-risk MDS patients,who are dependent on red-blood cell transfusion due to disease-related anemia, and who have a proven resistance towards treatment with erythropoetin-stimulating agents (ESA). The study randomizes patients to receive a treatment with the demethylating agent 5-azacytidine alone or in combination with an ESA. The study thus evaluates, if efficacy of 5-azacytidine, notably on the red-blood cell transfusion-dependence is comparable/inferior to a combination treatment with azacitidine and an ESA (that is if 5-azacytidine can overcome the resistance towards ESA). Being a phase II study, the study assesses, duration of erythroid response, overall survival and time to progression as well as toxicity.